A microfiche appendix including 1 sheet of microfiche and 44 frames is included herewith.
A. Field of Invention
The present invention relates to database systems for evaluation of items according to user preferences, and more particularly to database systems using domain specific knowledge and utility functions to identify items meeting user defined criteria.
B. Background of Invention
The proliferation of computers and of the exploding use of the Internet have brought with them the increasing availability of computerized databases of products, information, and services from which users, such as consumers or professionals, evaluate and purchase such items. However, the ever increasing availability of such databases to more and diverse types of users has resulted in a widening gap between the existing and the user required skills for using these databases.
There exists sophisticated tools for database mining, analysis and the subsequent generation of information from the extracted data, but none of these tools allow users to quickly and efficiently perform a frequently desired task of finding in the database the item most suited to the user""s objective and subjective preferences.
A typical activity involving this type of database access is online shopping: for example, a shopper is not interested in purchasing all of the VCRs that match her criteria, but only the one that gets closest to some xe2x80x9cideal VCRxe2x80x9d defined by the user""s own objective and subjective criteria (e.g., low cost, high performance, reliable, etc.). Conversely, even if no items match the shopper""s search criteria, she might still be interested in purchasing the item that is xe2x80x98closestxe2x80x99 or most similar to the her criteria. Current database access tools do not meet the following needs of such users for the following reasons.
First, conventional databases will often return empty search result sets where no matches found are found to the set of specific criteria input by a user; alternatively, they may return too many matches where very few critieria are specified. In either case, the user is unable to identify which items are most similar to her overall criteria, and must reformulate her search criteria.
Second, compound queries where multiple attributes are specified and which result in empty projections do not tell which criterion or group of criteria were responsible for reducing the number of matches to zero. Conversely, when too many matches are found, conventional tools provide no indication of the sensitivity of the database to each criterion. Thus, the user is unable to modify her criteria to eliminate such criteria, but must proceed by trial and error.
Third, shoppers compare items not on the basis of a single criterion, but using the concept of similarity given all or most critieria. For example, a car buyer who has identified a first car as a suitable item, may be looking for a less expensive car which implicitly would not only have a lower price tag, but simultaneously retain all other desirable features of the first car as much as possible. However, current database tools have the ability to evaluate items only along one dimension (e.g., price) without regard for the overall similarity of items along multiple dimensions, and thus are not suitable for this buyer to identify such a similar alternative car with similar features to the first car.
Fourth, many domains (automobiles, computers, financial instruments) are very complex and require significant expertise to understand at the database level (xe2x80x9cvariable valve timingxe2x80x9d, xe2x80x9c256K cachexe2x80x9d, xe2x80x9c0.14 negative market correlationxe2x80x9d). The typical consumer does not have sufficient expertise to evalute different items with respect to such technical data, but does know various high level critieria that are important to their decision making. The complexity of the underlying domain makes it difficult for a shopper to formulate a query that reflects his fuzzy needs and desires, resulting in a mismatch between the results the database provides and the user""s actual needs.
Finally, many shoppers are unable to describe what they are looking for with defined search criteria, but they can identify which items do not satisfy their requirements when such items are presented to them. With conventional tools, such shoppers are unable to deconstruct the domain into its constituent components and define useful search criteria which can then be used to select items from the database for further evaluation.
Accordingly, it is desirable to provide a database system that supports analysis and evaluation of the similarity of items in the database with respect to multiple critieria.
The present invention, a Database Evaluation System (DES), is designed to help consumers and business users alike to find the item(s) in a database that most closely matches their objective requirements and subjective preferences. It effectively turns a database of information-rich items into an interactive buyer""s guide.
The Database Evaluation System is a database technology focused entirely on the comparison and ranking of database items. The Database Evaluation System differs fundamentally from conventional database front ends in that it 1) uses a domain-specific vocabulary to isolate the user from potentially overwhelming amounts of raw data; 2) uses embedded expertise in the form of an xe2x80x9cevaluation recipexe2x80x9d to guide the user along an optimal decision path; 3) provides a unique, interactive, real-time user interface for selection and navigation of items in the database; and 4) accounts for subjective, fuzzily defined user criteria.
In one embodiment, the DES of the present invention provides a system for constructing and evaluating items in a database storing any plurality of items. An authoring module enables the creation of a domain model which captures expert level knowledge about an application domain and maps the knowledge onto the database, thereby organizing the data into a useful and meaningful structure. More particularly, the authoring module creates a domain model including a hierarchical plurality of attributes in which some attribute are hierarchically defined by other attributes. For example in an automotive domain, an attribute such as performance may be hierarchically defined by attributes such as acceleration, braking, handling and the like. Each of these may be further hierarchically defined. For the lowest level attributes that are not defined by other attributes, the authoring module allows for the association of such attributes to selected fields of the database, which define the actual data stored therein. The authoring module also enables the expert to define for each attribute a transfer function that maps the values of the underlying field of the database to a utility value of the attribute. The authoring module also provide for weighting the attribute relative to other attributes, thereby weighting the utility values of one attribute relative to the utility values of other attributes. Multiple domain models may be defined for a given database, and applied by end users during access and selection of items from the database. This enables the user to apply the expert judgments of various experts to the same database of information.
The DES further includes an evaluation engine which couples a domain model to the database and provides various user interfaces for end users to access and evaluate items in the database. A first user interface receives from the user for selected attributes a user defined utility function that describes the utility of various values of the attribute for the user. The evaluation engine selects for retrieval and display items of the database according to both the user defined utility function and the utility values of the selected attributes as defined in the domain model. Fuzzy logic may be used to match the user defined utility functions with the domain model functions and database items values. The selected items are iteratively displayed in reponse to each partial input of selected attributes by the user. This allows the user to iteratively reduce the number of items selected or retrieved from the database. From the selected items, the user may create a short list of items for further evaluation. This user interface thereby allows the user to quickly identify items of the database that match the user""s utility preferences, and to do so in an iterative, and interactive manner that progressively narrows the set of selected items of interest.
The system also includes a second user interface operating in conjunction with the evaluation engine that displays for each item on the user""s short list a relative score of the item to other items on the short list, and further displays for each attribute a direct manipulation mechanism, for example, a graphical slider. The user can manipulate the direct manipulation mechanism to alter the relative weighting of the attribute as defined previously in the domain model. The evaluation engine redetermines the relative score of each item in the short list according to any change in the relative weightings of the attributes, and updates the display of the recomputed scores. The user may iteratively change the weightings of attributes in this manner to determine the impact of such changes on the relative scores of the short list items. This user interface enables the user to comparatively evaluate multiple items simultaneously by adjustment of the attribute weightings.
The system further includes a proximity searcher user interface, also operating in conjunction with the evaluation engine. The proximity searcher provides for nearest neighbor navigation and evaluation by displaying one of the items of the database as a reference item. For attributes of the domain model, the proximity searcher also simultaneously displays a nearest neighbor item as a function of a distance between between reference item and the nearest neighbor item for the particular attribute. The nearest neighbor item is determined not merely by the item having the next closest value of an attribute, but rather, by weighting the distance between the reference item and the nearest neighbor item for the particular attribute by the overall distance between the items with respect to all other attributes. The user can select any nearest neighbor item and make it the reference item, such that the displays of all the remaining nearest neighbor items are updated accordingly. In this fashion the user can navigate through the database to explore the relationships and similarities between items of the database, and determine which items are similar and which are not. This process further aids the user in the selection and evaluation of items from the database, enabling the user to identify items that may have been previously overlooked.
In one embodiment, the proximity searcher is extended as a fractal or recursive searcher. Each of the attributes is associated with an attribute window pane, and the reference item is associated with a reference window pane. These windows panes are displayed simultaneously. For one of the attribute window panes, the database item therein is then treated as a reference item, such that another group of attribute window panes for the remaining attributes is again simultaneously displayed with the first group of attribute window panes. Each of these additional attribute window panes displays, for their respective attribute, a nearest neighbor item for the attribute, relative to the new reference item. This selection and expansion of attribute window panes into reference window panes may be repeated through several levels of simultaneous displays, thereby visually revealing a substantial portion of the underlying relationships of the items in the database.
The DES further supports users who do not know ahead of time the specific criteria or attributes they are looking for, but know what items or attributes are not satisfactory. The DES provides a method for critiquing items in the database to determine the user""s underlying criteria to determine which items the user would not select, and from there, eliminates from the database other items having attributes similar to these undesired items. In one embodiment, the DES presents to the user an item from the database for evaluation. The user inputs one or more reasons that the item is deficient or not satisfactory or would not be selected by the user. These reasons are associated with one or more attributes of the database, preferably according to a previously defined domain model. The utility value of the item""s attribute associated with the reason is then used to eliminate from consideration other items of the database having an equal or lesser utility value for this item""s attribute, and thereby having the same deficiency as the presented item. For example, if the user indicates that an item is too expensive, than other items having the same or greater cost are likewise eliminated. This process is repeated until the number of items for evaluation is reduced to a desired limit, thereby enabling the user to quickly reduce the number of items for consideration without having to pre-specify criteria in a search query.
Applications for the DES include interactive online shopping, electronic buyers guides, yellow pages, classifieds, and any other application where user needs to select and evaluate candidate items from a database of potential candidate using user defined, fuzzy criteria.
Items suitable for evaluation, inspection and/or purchase using the DES include consumer goods such as automobiles and home electronics; consumer services such as health care and insurance policies; financial services such as stocks, mutual funds and other investments; travel destinations and other hospitality services; real estate; electronic personals; personnel recruitment; and any other industrial or commercial goods.
The DES may be embodied in various platforms, including online environments such as commercial online services and the Internet; standalone applications in CD-ROM or floppy disk format; hybrids (CD-ROM with updating via online); and kiosks.